| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of forming proper images for a long period by suppressing excessive deterioration of a developer, even when a low-coverage continuous printing state continues for a long period. <P>SOLUTION: The image forming apparatus includes a developing device to which a fixed amount of carrier is supplied at intervals of a fixed time and to which, at intervals of a fixed set time, the amount of toner corresponding to a deficiency for a prescribed value of a toner concentration is supplied, when the toner concentration being in a toner deficient region A where the toner concentration is lower than the prescribed value, with a fixed amount of toner being supplied, in response to transition of the toner concentration from the toner deficient region A to an appropriate concentration region B where the toner concentration is equal to or higher than the prescribed value and is lower than an allowable limit value higher than the prescribed value, only carrier is supplied, in response to transition of the toner concentration to the appropriate concentration region B from a toner excessive region C where the toner concentration is equal to or higher than the allowed limiting value, and only the carrier is supplied, when the toner concentration is in the toner excess region C. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
